Facile synthesis of Co3O4@NiCo2O4 core-shell arrays on Ni foam for advanced binder-free supercapacitor electrodes

We developed a one-step hydrothermal strategy to fabricate Co3O4@NiCo2O4 core-shell arrays on Ni foam. With this method, the ultralong NiCo2O4 nanowires were self-assembled on the Co3O4 nanowire arrays on Ni foam comfortably. Moreover, the eletrochemical properties of the hybird eletrodes were elucidated by cyclic voltammograms, galvanostatic charge/discharge tests and eletrochemical impedance spectroscopy in 2 M KOH electrolyte. The results exhibited a specific capacitance of 672 F g−1 and excellent cycling stability (97.1% retention after 3000 cycles). The excellent electrochemical performance made the hybrid a promising electrode material for electrochemical capacitors.